If player does not press any keys nor no mouse activity for a certain time limit, a Screen Saver will take over the users screen; the user can easily terminate the screen save by having activity from either keyboard or mouse (just like a normal screen saver).

I remember seeing this in the 11th Hour game and absolutely loved how the image warped when the player goes inactive. Alas, I doubt I can make this work on ZDoom, but I might bring this back if I find out different.